1. Field of the Invention
The present invention pertains to generation of radio frequency electromagnetic signals, and, more particularly, synthesis of wideband radio frequency signals.
2. Description of the Related Art
One useful way to categorize radio frequency (“RF”) signals for some types of uses is by their bandwidth content. Two commonly used terms in this regard include “narrowband” and “wideband”. An ideal narrowband signal would comprise an infinitely long pulse containing a single frequency. An ideal wideband signal, on the other hand, is a “zero duration” pulse containing every frequency.
Thus, in general, wideband signals are traditionally generated using very short pulse widths—i.e., very short temporal pulses. These short pulses are typically less than 1 cycle of a narrowband signal. The short pulses generate frequency components across a broad band that is centered on the frequency of the narrowband signal. These short pulses therefore contain very broad frequency content.
There are a number of techniques currently employed for generating wideband signals. Perhaps the most common is the “spark gap discharge”. This mechanism is very similar to that by which a spark plug produces a spark in an internal combustion engine. The short duration discharge of energy generates a wideband signal.
However, the very nature of a time-limited pulse limits the amount of energy that can be contained in the pulse. This limit becomes quite stringent in a wideband signal because the pulse is so short. A known limitation of “traditional” wideband signals is the very high power and peak field required to propagate energy in the pulse. This often becomes the physical limitation in generating a wideband signal.
The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.